Pesticidal compositions and methods of killing pests using 2-alkinyloxyphenylcarbamates

ABSTRACT

2-Alkinyloxyphenyl-N-methylcarbamates are effective pest control agents, especially against insects and members of the order Acarina. They can be used by themselves or as active ingredients in pesticidal preparations.

This is a division of application Ser. No. 885,331, filed on Dec. 15, 1969, now abandoned.

The present invention relates to phenylcarbamates of the formula I, processes for their manufacture and their use by themselves or in preparations for controlling pests.

The present invention provides compounds of the formula I ##SPC1##

in which the substituents R₁ and R₂, independently of each other, each represents an alkyl group containing one to four carbon atoms, or in which one of these substituents may represent a hydrogen atom.

The present invention also provides a process for preparing the compounds of the above formula I, which comprises reacting a phenol of the formula ##SPC2##

With methylisocyanate, an N-methylcarbamic acid halide or with N-methyl-phenylcarbamate, or by first reacting a phenol of the above formula with COCl₂ to give the corresponding haloformic acid phenyl ester or to give the carbonic acid bisphenyl ester, and then reacting the ester with methylamine.

These new carbamates have a wide spectrum of biocidal properties.

They act especially as insecticides and acaricides, primarily against harmful orthoptera, colcoptera, rhynchotes, diptera and lepidoptera. They may be used for controlling a wide variety of storage pests and in domestic hygiene: cockroaches, mealworms, and especially against sitophilus species (corn weevil) which are difficult to control can be destroyed with very small amounts of the active substances.

Especially effective are those compounds of the formula I in which one of the substituents R₁ and R₂ represents a hydrogen atom, a methyl, ethyl or isopropyl group and the other represents a methyl, ethyl, propyl or isopropyl group.

Especially effective are the two compounds ##SPC3##

When used in large amounts, the compounds of the formula (I) display against various representatives of mono- or dicotyledonous plant types a growth inhibiting or growth delaying activity.

When used in plant protection in a concentration which does not produce any phytotoxic effects they display an outstanding activity against harmful microorganisms, for example against fungi, for example, against Altenaria solani, Phytophthora infestans and Septoria apii, also against harmful nematodes and their eggs or larvae.

Furthermore, the new substances act quite generally as microbicides, for example, against Aspergillus species. They also act against molluscs.

The new preparations can be used in a wide variety of ways and in different forms, for example, in the form of sprays, dusting powders, so-called fly plates or tapes, impregnated with a solution of the active substances, as is generally known to experts and for which applications the present invention provides a few examples. Compare in this connection also U.S. Pat. No. 3,329,702 or British Pat. No. 1,047,644 or Swiss Pat. No. 424,359.

In many cases, as, for example, in combating soil insects, the use of granulates is of advantage to ensure that the active substances are given off uniformly over an extended period of time. Such granulates can be prepared by dissolving the active substance in an organic solvent, absorption of this solution by a granulated material, for example attapulgite or SiO₂ or by adsorptive organic high polymers and removal of the solvent. The granulates can also be prepared by mixing an active substance of the formula I with a polymerisable compound, then polymerising the mixture, without affecting the active substance, and carrying out the granulation during the polymerisation.

In whatever form such preparations are they may be distributed (by spraying or dusting) over large surfaces with the aid of aircraft.

The concentration in which the preparation is applied may vary within wide limits depending on the purpose in hand and is in general from 0.01 to 20 % by weight for rather dilute preparations, while more concentrated ones contain 20 to 98 % by weight of active substance.

By admixture of synergists the activity of the carbamates of this invention can be further increased; for this purpose there are suitable, for example, sesamine, sesamex, piperonylcyclonene, piperonylbutoxide, piperonal bis[2-[2-butoxyethoxy]ethyl]acetate, sulphoxides, propylisome, N-(2-ethylhexyl)-5-norbornene-2,3-dicarboxamide, octachloro-dipropyl ether, 2-nitrophenyl-propargyl ether, 4-chloro-2-nitrophenyl-propargyl ether and 2,4,5-trichlorophenyl-propargyl ether.

The various forms of application of such preparations can be adapted to the individual purpose by admixing with them substances that improve the distribution, the adhesion, the stability towards rain and possibly the penetration, for example, fatty acids, resins, wetting agents, glue, casein or alginates.

The preparations according to this invention may be used by themselves or in conjunction with conventional pest control agents, for example, herbicides, insecticides, acaricides, nematocides, bactericides, fungicides or molluscicides.

The following Examples illustrate the invention. The parts are by weight unless otherwise indicated and temperatures are shown in degrees centigrade.

EXAMPLE 1

2-butinyloxyphenol

A solution of 122 parts of p-toluenesulphonic acid-2-butinyl ester in 150 parts by volume of acetone is dropped into a boiling mixture of 66 parts of pyrocatechol, 75 parts of potassium carbonate, 91 parts of potassium iodide and 360 parts by volume of acetone. The suspension is refluxed for 24 hours, then cooled, filtered and evaporated. The residue is taken up in ether, repeatedly washed with water and while being cooled with ice extracted with 200 parts by volume of sodium hydroxide solution of 10 % strength. The alkaline extract is neutralised with hydrochloric acid and the product taken up with chloroform. The solvent is evaporated and the product distilled at a bath temperature of 120°C under 0.05 mm Hg pressure. The distillate crystallises; it melts at 43° to 46°C.

2-(2-butinyloxy)phenyl-N-methylcarbamate

A solution of 56 parts of 2-(2-butin-1-yloxy)phenol in 150 parts by volume of ethyl acetate is mixed with 0.5 part of triethylenediamine and then portionwise with 21 parts of methylisocyanate.

The mixture is kept for 24 hours at 40°C and then evaporated. The residue is crystallised from chloroform+ cyclohexane; it melts at 79° to 81°C (Compound No. 1).

EXAMPLE 2

2-(1-butin-3-yloxy)phenol

A solution of 247 parts of p-toluenesulphonic acid-1-butin- 3-yl ester in 200 parts by volume of acetone is dropped at 50°C into a suspension of 110 parts of pyrocatechol, 152 parts of anhydrous potassium carbonate and 166 parts of potassium iodide in 100 parts by volume of acetone. The mixture is refluxed for 2 days, then filtered and evaporated. The residue is taken up in 500 parts by volume of ether, washed with water and with 450 parts by volume of sodium hydroxide solution of 20 % strength. The alkaline extract, together with the partially precipitated sodium salt of the product, is acidified with semidilute hydrochloric acid while being cooled with ice. The product is obtained by extracting this solution with chloroform and evaporating the extract. For purification it is distilled under a high vacuum. Boiling point: 63° to 66°C under 0.07 mm Hg. The distillate crystallises; it melts at 52° to 54°C.

2-(1-butin-3-yloxy)phenyl-N-methylcarbamate

A solution of 45.5 parts of 2-(1-butin-3-yloxy)phenol and 0.1 part of triethylenediamine in 150 parts by volume of carbon tetrachloride is mixed with 19 parts of methylisocyanate. The mixture is stirred for 14 hours at 40°C. The resulting crystalline product is filtered off and once recrystallised from toluene. It melts at 88° to 91°C (Compound No. 2).

The following compounds may be prepared by the same or a similar method:

1. 2-(2-Butinyloxy)phenyl-N-methylcarbamate,

2. 2-(1-Butin-3-yloxy)phenyl-N-methylcarbamate,

3. 2-(2-Pentin-4-yloxy)phenyl-N-methylcarbamate,

4. 2-(2-Pentin-1-yloxy)phenyl-N-methylcarbamate,

5. 2-(1-Pentin-3-yloxy)phenyl-N-methylcarbamate, and

6. 2-(2-Methyl-4-pentin-3-yloxy)phenyl-N-methylcarbamate.

EXAMPLES OF FORMULATIONS

Dusting agent

Equal proportions of an active substance of this invention and of precipitated silicic acid are finely ground together. When this powder is mixed with kaolin or talcum, there result dusting agents preferably having a content of 1 to 6% of active substance.

Spray powder

To manufacture a spray powder, for example, the following ingredients are mixed and finely ground together:

50 parts of an active substance according to this invention

20 parts of HISIL (highly adsorptive silica)

25 parts of bolus alba (kaolin)

3.5 parts of a reaction product of p-tertiary octylphenol with ethylene oxide

1.5 parts of sodium salt of 1-benzyl-2-stearyl-benzimidazole-6,3'-disulphonic acid.

Emulsion concentrate

Readily soluble active substances can also be formulated as emulsion concentrates in the following manner:

20 parts of active substance

70 parts of xylene

10 parts of a mixture of a reaction product of an alkylphenol with ethylene oxide, with calcium dodecylbenzenesulphonate

are mixed together. When this mixture is diluted with water to the desired concentration, a sprayable emulsion results.

Granulate

A solution of 7.5 g of an active substance of the formula I in 100 ml of acetone is poured over 92 g of granulated attapulgite (mesh width: 24/48 mesh per inch). The whole is thoroughly mixed and the solvent removed in a rotary evaporator. The resulting granulate contains 7.5 % of active substance.

EXAMPLE 3

To test the effect against various storage pests, 2 g of the Compound No. 2 were mixed with 38 g of talcum and the whole was very finely ground. In this manner a dusting powder of good efficacy was obtained, with which the following results were achieved:Organisms tested Minimum concentration needed for 100% lethal effect within 24 hours' exposure (mg of active substance per square meter) Compound Compound No. 2 No. 1______________________________________German cockroach 3 6(Phyllodromia germanica)American cockroach 1.5 25(Periplaneta americana)Russian cockroach 6 25(Blatta orientalis)Yellow mealworm beetle(Tenebrio molitor) imago 50 100 larva 200 200Bacon beetle(Dermestes frischii) imago 100 50 larva 50 100Grain weevil 25 200(Sitophilus granarius)Fur beetle larva 200 100(Attagenus piceus)House cricket 12 25(Acheta domestica)______________________________________

EXAMPLE 4

lucilia sericata (Blowfly)

Freshly hatched maggots in small glass vessels were fed horseflesh which had been treated with an aqueous emulsion of the substance under test. The determination of the limit concentration of the active substance was performed in three test series on different days, in which new fly generations and new dilution series of 100, 48, 24, 12, 6, 3 and 1.5 ppm were used. After 24 hours the following limit values for a 100 % lethal effect were obtained:

Compound No. 1 at 3 ppm

Compound No. 2 at 3 ppm

EXAMPLE 5

Activity against female mosquitoes (Aedes aegypti)

Female mosquitoes were kept for 6 hours in Petri dishes coated with the substance under test. To produce this coating the bottom half of the dish was first treated with 1 ml of an acetonic solution of the substance and then dried for 1 hour. The solutions used contained 1,000, 100, 10 and 1 ppm respectively, which corresponds to a concentration of 1, 0.1, 0.01 and 0.001 mg per dish. The mosquitoes were cooled in ice and 10 females were counted into each dish. For every concentration 4 parallel tests were made.

After 90 minutes the following LD₁₀₀ values were recorded:

    Amount applied                                                                 (mg per dish)                                                                               1        0.1      0.01   0.001                                    ______________________________________                                         Compound No. 1                                                                              100 %    100 %    100 %   75 %                                    Compound No. 2                                                                              100 %    100 %    100 %  100 %                                    ______________________________________                                    

EXAMPLE 6

cimex lectularius (Bed bug)

In a similar test to that described in Example 5, in which the active substance is tested on filter paper in plastic dishes (1 mg per dish corresponds to 1 g per 6 m²), and which was repeated twice with 10 bugs each, resulted for the active substance No. 2 at a concentration of 10, 1 and 0.1 mg/dish in a 100 % lethal effect in each case.

EXAMPLE 7

Contact effect against Ceratitis capitata

The bottom half of each Petri dish was treated with 1 ml of an acetonic solution of the substances Nos. 1 and 2 each, which solution contained a specified quantity of active substance. Then the solvent was expelled and deep-cooled fruit flies were placed in the prepared Petri dishes and the lids were then put on. Each dish contained 10 flies. After 1 hour the lethal effect achieved with different concentrations of a dilution series was examined:

    Concentration                                                                              Compound No. 1  Compound No. 2                                     (ppm)                                                                          ______________________________________                                         1000        100 %           100 %                                              100         100 %           100 %                                              10          100 %           100 %                                              5           100 %           100 %                                              2.5         100 %           100 %                                              1.25        100 %            50 %                                              ______________________________________                                    

EXAMPLE 8

Stomach and contact effects against Orgyia gonostigma and Epilachna varivestis

Young mallow plants (Malva sylvestris) in pots with about six leaves were immersed in a solution of the active substance of a specific concentration and allowed to dry. Over every plant a cellophane hood containing larvae of Orgyia gonostigma in the L₃ stage were then placed and fastened with a rubber band. The insecticidal stomach and contact effects were examined 2 and 5 days later. When at the first examination 100 % mortality is found, the plant is reinfested so that at the same time the activity of the aged preparation can be determined.

The test with larvae of Epilachna varivestis in the L₄ stage was carried out in an identical manner with Phaseolus as host plant.

a. Effect against Orgyia

    Concentration                                                                            Compound No. 1  Compound No. 2                                       (ppm)     after           after                                                        2 days   5 days   2 days    5 days                                     ______________________________________                                         800       100 %      100 %    80 %    100 %                                    400       100 %       80 %    80 %    100 %                                    200        80 %      100 %    80 %    100 %                                    100        60 %      100 %    --      --                                       ______________________________________                                    

b. Effect against Epilachna (after 5 days)

    Concentration                                                                              Compound No. 1  Compound No. 2                                     (ppm)                                                                          ______________________________________                                         800         100 %           100 %                                              400         100 %           100 %                                              200         100 %            60 %                                              100          80 %           --                                                 ______________________________________                                     

I claim:
 1. A method of combating insects and acarids which comprises applying thereto an insecticidally and acaricidally effective amount of a compound of the formula ##SPC4##in which each of R₁ and R₂ represents alkyl of from one to four carbon atoms or one of R₁ and R₂ represents hydrogen.
 2. The method of claim 1 in which one of R₁ and R₂ represents hydrogen, methyl, ethyl or isopropyl and the other represents methyl, ethyl, n-propyl or isopropyl.
 3. The method of claim 2 in which the compound is ##SPC5##
 4. The method of claim 2 in which the compound is ##SPC6##
 5. The method of claim 2 in which the compound is ##SPC7##
 6. An insecticidal and acaricidal composition which comprises (1) as active ingredient an insecticidally and acaricidally effective amount of a compound of the formula ##SPC8##in which each of R₁ and R₂ represents alkyl of from one to four carbon atoms or one of R₁ and R₂ represents hydrogen, and (2) a carrier. 